1. Field of the Invention
The present invention relates to an image bearing member and a manufacturing method therefor and an image forming apparatus which uses the image bearing member, and in particular, to an image bearing member having a filling-up member fixed to the cylindrical member thereof which is used, for example, in a copying machine, a printer, a facsimile machine, a multi-functional machine thereof and the like, to a manufacturing method thereof, and to an image forming apparatus using the image bearing member.
2. Discussion of the Background
A drum-shaped image bearing member which is used for an electrophotographic image forming apparatus is composed of a hollow cylindrical member of which a photosensitive layer, conductive layer and the like are coated on the outer peripheral surface of the cylindrical member.
In an electrophotographic image forming apparatus, an image is formed by transferring a toner image to a transfer sheet and fixing that on the transfer sheet after forming an electrostatic latent image on the image bearing member as a photoconductive element, and developing the toner image. Various methods of manufacturing a cylindrical photoconductive drum, namely, an image bearing member have been conventionally proposed.
For example, in a case of obtaining a construction for supporting both ends of opening portion of the cylindrical member by inserting a flange into an inner peripheral surface of the hollow cylindrical member as an image bearing member and fixing that thereto, fitting art is known in which adhesive having a quick hardening ability and an elasticity after complete hardening is applied onto an inner peripheral surface of the cylindrical member or an external peripheral surface of the flange. See Japanese Laid-open Patent Publication No. 6-282204/1994. There, the flange is press fit onto the inner peripheral surface of the hollow cylindrical member employed as the image bearing member, and thereafter both elements are combined with adhesive, and thereby a structure of supporting the both-ends releasing portions of the above cylindrical member can be obtained. On that occasion, grooves are provided adjacently to the both sides of the adhesion part. In such structure, when the flange is fixed so as to press fit in the cylindrical member, excess adhesive applied to the adhesion part is intercepted by the grooves thus provided adjacent thereto. Consequently, the excess adhesive flowing out from the adhesion part can be prevented from adhering on the image bearing member, etc. at the time of inserting the adhesive or using the apparatus. Such related art as mentioned above is well known. See Japanese Laid-open Patent Publication No. 4-84182/1992.
However, there has been a shortcoming that, in a case of applying the image bearing member having aforementioned construction to an electrophotographic copying machine, in which electrophotographic method is used, performance deteriorates due to occurring of noise by trembling a cleaning blade which rubs with the surface of the image bearing member when performing a charging operation, driving the image bearing member or the like, and stopping an image forming operation, if the image forming operation is performed in an image forming process including a process of charging by contacting a charging member in which voltage is applied thereof with the image bearing member.
To solve such a shortcoming, a related art of suppressing the occurrence of noise due to vibration of the image bearing member when charging, by mounting a weight member inside the image bearing member press fit via an elastic member between the inner peripheral surface of the image bearing member and the outer peripheral surface of the weight member, is known. See Japanese Laid-Open Patent Publication No. 5-35166/1993.
However, in such an image bearing member, and a manufacturing method thereof and an image forming apparatus which uses the image bearing member, it is difficult to press fit the weight into the image bearing member although it is required to press fit via the elastic member having a hardness of 20 degrees through 70 degrees JIS (Japanese Industrial Standard). Especially in the case of manufacturing the image bearing member using thin material, a variation from swelling is caused with inner pressure due to press fitting operation of the elastic member. Further, if such an image bearing member is used for an image forming apparatus, the manufacturing cost is increased and it is also difficult to obtain a high quality image.
In addition, suppressing noise which occurs due to vibration of the image bearing member by adhering a filling-up member having a slight taper at a side to an inside of the image bearing member by first applying an epoxy resin adhesive onto an inner peripheral surface of the image bearing member then inserting the filling-up member, or after applying the epoxy resin adhesive onto an outer peripheral surface of a filling-up member made of a rigid body or an elastic member, inserting the filling-up member into an inside of the cylindrical image bearing member is known. See Japanese Laid-Open Patent Publication No. 5-35167/1993 and Japanese Laid-Open Patent Publication No. 8-146637/1996.
However, in the related art, applying epoxy resin adhesive onto an inner peripheral surface of the image bearing member, or onto an outer peripheral surface of a filling-up member is difficult, and there has been a shortcoming that an inferior product is made due to adhering or scattering of the excess adhesive to both end faces of the filling-up member or the image bearing member when inserting the filling-up member. Furthermore, it has also been difficult to press fit the filling-up member into the inside part of the image bearing member via the adhesive.
In particular, it takes a relatively long time to insert and fix the filling-up member with the epoxy resin adhesive or the like, and the image bearing member made of a thin material is deformed, therefor resulting in an inferior product because of variation due to swelling from the inner pressure caused by press fitting the filling-up member. Namely, in a case of using such an image bearing member as an image forming apparatus, it takes from 30 minutes to several hours for adhering the filling-up member to the image bearing member with an epoxy resin or epoxy two-liquid adhesive agent, and further, even a 5-minutes-hardening-type two-liquid adhesive takes 5 minutes for starting hardening from liquid state, and further, it takes from 30 minutes to several hours for reaching an actual hard state. Therefore, it requires high costs and is also difficult to obtain a high quality images. In a case of an image bearing member made of thin material, the shape of image bearing member can swell or otherwise deform due to the inner pressure caused by inserting the filling-up member into the image bearing member. If such image bearing member is used for the image forming apparatus, the manufacturing costs of the apparatus are increased due to the long curing time required, and it is more difficult to obtain a high image quality due to the deformations.